Once upon a time, this used to work, and I kept the configuration the same, but... now nothing.

I'm just trying to get an NFS server set up on a FreeBSD 4.9 server. The process should be about as complicated as this:

Add this entry to /etc/exports:

/var/home /var/vpopmail/domains -maproot=root XXX.XX.XX.XXX

Execute this:

portmap
nfsd -u -t -n 4
mountd -r

Then this should work, regardless of network and firewall issues:

showmount -e localhost

But showmount -e localhost fails with the following error:

RPC: Port mapper failure
showmount: can't do exports rpc

And even if I kill off the NFS daemon, and try a rpcinfo -p localhost, I get this error:

rpcinfo: can't contact portmapper: rpcinfo: RPC: Unable to receive; errno = Connection reset by peer

The portmapper is still running. Why the heck does nothing work as if it isn't?

Edit to add:

FYI: Sockstat gives me this:

$ sockstat |egrep "(nfsd|portmap)"
root     nfsd     86310    3 udp4   *:2049                *:*                  
root     nfsd     86310    4 udp4   *:973                 *:*                  
root     portmap  45920    0 tcp4   *:111                 *:*

Then, at a later time (say, 5 minutes) it's as if nfsd isn't acting as a server:

$ sockstat |egrep "(nfsd|portmap)"
root     portmap  45920    0 tcp4   *:111                 *:*

But the nfs daemon is still running:

$ ps ax |grep nfsd
86311  ??  I      0:00.00 nfsd: server (nfsd)
86312  ??  I      0:00.00 nfsd: server (nfsd)
86313  ??  I      0:00.00 nfsd: server (nfsd)
86314  ??  I      0:00.00 nfsd: server (nfsd)